The overall objective of this project is to describe the cellular mechanisms by which secretagogues control H+ ion secretion in parietal cells from the gastric mucosa. The studies will involve the use of isolated gastric glands and the development of a functional preparation of isolated parietal cells with which to study receptor mechanisms, the role of cyclic nucleotides, calcium and protein kinase as well as identification of phosphorylated intermediates. These techniques will be used in conjunction with the previously established indices of cellular acid secretory responsiveness, respiration, aminopyrine uptake and morphological transformations, to establish a temporal and kinetic relationship between the various reactions. Measurement of these physiological and biochemical paramenters will provide a basis for the characterization of the sequence of events occuring between hormone-receptor interaction and activation of the H+ ion "pump."